This short communication presents a review on the work of the mycological laboratory of the Institute of Microbiology and Epidemics, Hannover, Germany, concerning the mycological investigation on feeding stuff. Out of the routine diagnostic work, examining more than 4000 probes in the last 10 years, some selected investigations on scientific questions will be mentioned. Different subjects as the influence of homogenisation of feeding stuff on the mycological evidence rate, the microbiological status of germinating feeding stuff for pet birds the contamination of wheat with Fusarium spp. after fungicidal treatment will be discussed. Out of the great number of diagnostic investigations the most often examined feeding stuffs, those for pigs, will be looked at more closely. The evidence rate of yeasts and moulds and the number of isolated fungi are demonstrated.